As getting smaller and integrated, electronic devices and data communication devices are affected more by heat, static electricity, or electromagnetic waves. For example, since, as electronic components, as a microprocessor has a higher processing speed and a memory semiconductor has a larger capacity and increased integration degree, ambient heat, static electricity, and electromagnetic waves have a large impact on the microprocessor and memory semiconductor.
Accordingly, it is necessary to quickly discharge heat generated by an electronic component mounted therewith, such as an integrated circuit (IC) and a light emitting diode (LED) or a heat source such as an electronic component module.
For this, there is generally used a method of discharging heat through a thermoelectric element by interposing the thermoelectric element between a case which accommodates electronic components that generate heat and a heat source to use the case as a cooling unit.
For example, a thermoelectric sheet is used to quickly transfer heat generated by an IC or a display provided at a smart phone to another place to cool the IC or display. As thermoelectric sheet, a graphite sheet which has a small thickness and flexibility, a heat-conductive silicone rubber sheet, a heat pipe, or the like may be used.
A heat-conductive silicone rubber sheet has elasticity and flexibility but has a disadvantage of lower heat conductivity than that of a graphite sheet or heat pipe. Particularly, heat conductivity in a surface direction is lower than that in a thickness direction.
Since a graphite sheet is formed by stacking and pressurizing flake powder, heat conductivity is high about 1,000 W in a surface direction but is lower in a thickness direction than that in the surface direction.
As a heat emitting sheet to which a graphite sheet is applied, Korean Patent Registration No. 755014 discloses a technology in which a thermoelectric adhesive manufactured by mixing poly dimethylsiloxane, silicone resin, and thermalconductive fillers is applied to one side of a graphite heat emitting sheet and a poly(methyl methacrylate)-trialkoxysilane copolymer coating solution is applied to the other side thereof to be easily stuck to a display product, to have heat conductivity, and to prevent graphite powder from scattering.
However, according to the above-described configuration, a heat emitting sheet is supplied in a roll shape and cut by a consistent length to be used. Here, since a graphite sheet is exposed at a section and has a flake structure in which leaves are piled up in a thickness direction, graphite powder scatters at the section and the heat emitting sheet is easily separated from the graphite sheet.
Also, when a coating solution is applied to one side of the graphite sheet and the heat emitting sheet is interposed between objects, since one object is in contact with a thermal conductive adhesive and the other object is in contact with the coating solution, there is a problem in which heat conductivity is decreased.
Also, there are problems such as an unreliable contact between objects which face each other and inadequate absorption of shocks applied to the objects.